The MIB module for managing Trunk Media Gateway.  

A Media Gateway is a network element that provides conversion 
between the audio signals carried on telephone circuits and 
data packets carried over the Internet or over other packet 
data networks. 

Trunk Media Gateway interface is between the telephone network 
and a Voice over IP/ATM network. 
The interface on a Trunk Gateway terminates a trunk connected 
to PSTN switch (e.g., Class 5, Class 4, etc.).

Media Gateways use a call control architecture where the call
control 'intelligence' is outside the gateways and handled by
external call control elements, called Media Gateway 
Controllers (MGCs). 
The MGCs or Call Agents, synchronize with each other to 
send coherent commands to the gateways under their control.

MGCs use master/slave protocols to command the gateways under 
their control.  Examples of these protocols are:
  *  Simple Gateway Control Protocol
  *  Media Gateway Control Protocol
  *  Megaco (H.248)
  *  Simple Resource Control Protocol

To connect MG to MGCs using these control protocols through 
an IP/UDP Ports which must be configured. To resolve IP 
Addresses, DNS name services may be used.